The present invention relates generally to the production of bent sheets or plates of glass and, more particularly, to an improved electrical contact assembly employed in apparatus for bending glass sheets to relatively sharp angles.
In accordance with the well-known gravity method for bending glass sheets, such as are intended for use as glazing closures in vehicles and the like, a flat sheet of glass is supported upon a so-called skeleton or outline-tyep bending mold having a substantially continuous shaping surface curved in outline and elevation to the curvature to be imparted to the glass sheet. The mold and sheet are passed through a bending furnace in which the sheet is heated to the softening point of the glass so that it sags by gravity into contact with the shaping surface of the mold and assumes the curvature thereof. The mold can be sectionalized to permit relative movement of the sections during the sagging of the heated glass to impart rather complex curvatures to the glazing closures incorporated in modern-day vehicle designs, for example. After bending, the glass sheet can be annealed or it can be tempered by subjecting the opposite surfaces of the heated sheet to jets or blasts of a cooling medium such as air.
In addition to the complex curvatures mentioned above, it is sometimes desirable to provide a relatively sharp angled or V-shaped bend in the glazing closure transversely or longitudinally thereof along one or more lines to effect wrap-around of the windshield or backlight into the roof line of the vehicle or into the side surfaces thereof. The formation of such bends, i.e., sharp V-shaped bends or bends having very small radii of cruvatures, by the above-described "gravity" bending technique poses problems in fabrication.
Such problems were solved by the glass bending methods disclosed and claimed in U.S. Pat. Nos. 3,762,903 and 3,762,904, assigned to the same assignee as the present invention, whereby an electrically conducting path is formed on at least one surface of the glass sheet along the line about which it is desired to sharply bend the sheet. The sheet is then supported on a suitable gravity mold structure and heated in the furnace to a temperature corresponding to the softening point of the glass, causing it to sag by gravity into conformance with the shaping surfaces of the mold while simultaneously passing an electric current through the electrically conducting path to heat the area of the glass sheet immediately adjacent said path to a temperature above the aforementioned softening point, causing the sheet to bend along such path to form the desired relatively sharp angle therein. In order to provide for a completely automated, mass production operation, a mold apparatus, as described and claimed in U.S. patent application Ser. No. 558,288, filed Mar. 14, 1975, now Pat. No. 4,002,450 and assigned to the same assignee as the present invention , was developed to include electrical conducting means in the mold for supplying electrical current from a suitable source to the electrically conducting path in the glass sheet automatically during the advancement of the sheet through the heating furnace.
Such electrical conducting means on the mold include contactors adapted to engage electrically conducting lines formed on the edges of the sheet and leading to the electrically conducting path about which the glass is to be bent. The present invention constitutes an improvement over the invention escribed and claimed in the aforesaid patent application Ser. No. 558,288 by making certain improvements in the electrical contactors to assure continuous contact with the electrical conducting lines formed on the glass sheet and uninterrupted current flow thereto during the bending of the sheet and displacement of the contactors from the sheet into an out-of-the-way position after bending to facitlitate the removal of a finished bent sheet from the mold and the replacement thereof with a fresh sheet.